Engine problems

I have a 2002 liberty with a big engine problem. It all started 4/8 - my chck engine light went on. I immediately brought it to a local mechanic since I have 75k miles on it & no more warranty. Code 304 - 4th cylinder misfiring...replaced the coil pack/full tune up. Next day, started up truck, engine light now flashes at me and you can hear the misfire. Shut it off, start it up, the engine light is back on, runs great. Bring it back to mechanic. He checks, again 4th misfiring. Replaces coil pack (defect he says), get it back. Runs great for 3 whole days. One morning, again, engine light flashes at me. Code 304 again. Shut if off, restart, runs great, light remains. Bring it back. Mechanic resets. Things look great. Have it back 1 day, again, but yet, code 302 - now its cylinder 2 misfiring. Damn. Bring it back. He replaces the coil pack in cylinder 2 - get it back. Very next morning, truck does not sound healthy. Engine light flashing at me...knock in the engine..doesn't sound good. Bring it back. 4th spit out my rocker arm and lifter for the push rod. Ok, fix it. Done. Next day, same thing. Ok, replace the rocker arm again, spring, lifter, coil pack. Got it back, didn't even drive 30 miles and check engine light is back. Take it home, next morning,...knock, knock, knock in the engine. Damn. Not liking codes 302 or 304. I just stole it back from my mechanic when the shop was closed...had it towed to a dealer now since it's obvious mechanic doesn't know Jeeps. Now it's sitting at a dealer and my worse fear..blown head gasket. Has anyone here had any problems like this or am I just cursed with a bad Jeep??? Any feedback would be greatly appreciated as I'm livid.

Which engine do you have, the 4 cylinder or the 3.7 V6? I know that Chrysler's have quite a history of blown head gaskets in the 4 cylinder engines, but I don't know if the 4 cylinder libby has issues like this. I can tell you from experience that I've replaced blown head gaskets in my 87 Dodge Aries, 91 Plymouth Acclaim, my friend's 96 Neon, my parents 96 Stratus......the list goes on and on. So if it's the 4 cylinder you have.......well.........

Which engine do you have, the 4 cylinder or the 3.7 V6? I know that Chrysler's have quite a history of blown head gaskets in the 4 cylinder engines, but I don't know if the 4 cylinder libby has issues like this. I can tell you from experience that I've replaced blown head gaskets in my 87 Dodge Aries, 91 Plymouth Acclaim, my friend's 96 Neon, my parents 96 Stratus......the list goes on and on. So if it's the 4 cylinder you have.......well.........

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Those headgasket issues with the 4 cylinder engines was fixed around '97/'98 for future reference. (whistle)

Sorry to hear about your problems.... what engines are they replacing?

If it's a blown head gasket, coolant should be inside the engine with the oil. If you can, check it and see if your oil looks like normal oil should. If it looks/smells like coolant, it probably is the head gasket, and the engine is toasted.

very interesting that this is the 3rd one according to your dealer that blew up, as this is the first i've read about it.

Might have to do some research on this one.....I don't like the sound of this.

I have the same problem with my nephews 2002 jeep liberty I have the rockers popping off and all rockers and lifters have been replaced it is only on the right side head this jeep has only 48,748 miles he purchased it 9/7/2005 only put 2,000 miles on it this is the third time they poped off dealer fixed and then Technition replaced all lifters and rockers and tested all spring tentio can some one help with this problem? does the cam flex in these engines

Now that I think about it, the 3.7 doesnt have lifters. Its an OHC and the rockers ride right on the cams do they not? No push rods either. This set up is supossed to last along time from what Ive heard.

The 3.7L has aluminum heads, and therefore must have hardened steel valve seats pressed into the head. Unfortunately these sometimes come out. My guess is the engine was severely overheated perhaps? I am guessing here, I really don't know what causes it. If the head gasket were leaking there would be water in the oil and or exhaust of course. I suspect there may be a TSB about it, since the dealer wants to tell the owner it is a head gasket, when it is obviously not the case.
There are cam followers that Mopar calls rocker arms on the 3.7L. They are real nice steel stampings and they have rollers on the end, so in effect they are roller rockers; good stuff. Since more than one cylinder is doing this, and since they are all even numbered, it is obviously all on the same cylinder head. That head got hot, really hot, or maybe Chrysler did not seat the valve seats properly when they made it. The dealer should be happy to tell you all about it, were it out of warranty, but since they hide the real culprit, i suspect there is a TSB. A TSB means warranty, so the dealer won't make near as much from Chrysler Jeep as they would from the customer. Therefore the incentive to misstate the facts about this failure.
I would search around, ask them to show you the head soon as it is off if possible. You can about count on it, the valve seats came loose, causing incorrect valve train geometry, and therefore broken valve train parts.

I wonder if the 4.0L in-line 6 from the cherokee will fit under the hood? Nothing stopped those engines. I'm almost hoping mine blows! Then I can justify puting a 5.7 hemi crate motor in there laugh.gif

Yeah the Rambler six is a good engine, certainly reliable. I don't think it comes close to the 3.7L myself for a lot of reasons. First off i should say i have never seen or heard of a 3.7L having loose valve seats; however it is clearly the most likely culprit for the one described here. I recently saw a 3.8L Chrysler minivan do this same thing, with the back cylinder head. I have come across it several times with other makes however, mostly Japanese engines with aluminum cylinder heads requiring the valve seat be pressed in, ironically just as cast iron heads have since the `20s; but cast iron heads hold it a lot better. Never heard of this phenomenon before the `80s.
The 3.7L has Mercedes style lifters and rocker arms; and the really nice Mercedes style timing chains as well, very reliable, and long lived. I suspect this head got hot, very hot, or the dude manufacturing the head had a bad day when installing the valve seats. When this happens it is almost always the exhaust valves, so it would seem heat is a factor to me.